Distorted image texture on curved plane
The easiest way to fix this is to project the texture from a perspective view and then manually adjust the top and bottom edges to remove their curve. To do this press 1, as you are looking down the Y axis, and press the middle mouse button to exit orthographic view. Select the entire surface and press U then V to project from view. Then open the UV Editor layout. Select all the points on one of the curved edges and straighten them out by pressing S, Y, 0, and do the same to the other curved edge.